Increased disk utilization and queue size in accounting data after updating to kernel-3.10.0-1160.15.2.el7
Issue
- Increased disk utilization and queue size after updating to kernel-3.10.0-1160.15.2.el7
- Issue does not show on kernels prior to
kernel-3.10.0-1160.15.2.el7
(note, patch was actually done in kernel-3.10.0-1160.13.1.el7, but that was not released) - Issue is only shown by an increase in the accounting numbers; no actual performance issue exists.
- Evident when comparing prior kernel accounting data to new kernel accounting data
- For example, note the increased %util on similar operations:
kernel-3.10.0-1160.11.1.el7
===========================
11:50:01 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util
Average: dev259-0 1330.84 8635.72 43590.53 39.24 0.53 0.39 0.04 5.93
Average: dev259-1 1336.13 8582.11 43758.02 39.17 12.77 9.32 0.04 5.99
Average: dev259-6 1364.61 9004.60 43878.10 38.75 0.43 0.31 0.04 6.12
Average: dev259-9 1365.20 9010.97 44383.64 39.11 1.87 1.35 0.04 6.01
Average: dev259-12 1357.83 8800.33 44060.89 38.93 2.85 2.05 0.04 6.04
Average: dev259-13 1360.67 9387.25 43672.18 39.00 0.51 0.37 0.05 6.15
kernel-3.10.0-1160.21.1.el7
===========================
11:50:01 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util
Average: dev259-0 1863.29 7101.66 54567.36 33.10 8.84 4.74 0.10 18.18
Average: dev259-4 1832.84 6809.61 54489.68 33.45 5.35 2.92 0.09 17.06
Average: dev259-3 1825.97 6825.86 54364.51 33.51 4.68 2.56 0.09 16.98
Average: dev259-9 1889.48 7099.16 55319.70 33.04 9.77 5.17 0.09 17.07
Average: dev259-10 1860.63 6895.86 54649.01 33.08 10.55 5.67 0.09 16.85
Average: dev259-11 1873.74 7405.25 54449.48 33.01 6.71 3.58 0.10 18.01
Environment
- Red Hat Enterprise Linux 7
- kernel-3.10.0-1160.15.2.el7 or newer
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